Primary Adenoid Cystic Carcinoma of the Esophagus : An Immunohistochemical and Electron Microscopic Study

Immunohistochemical and electron microscopic findings of a primary adenoid cystic carcinoma of the esophagus from a 71-year-old male patient are described. An oval tumor in the middle intrathoracic esophagus was resected. The tumor appeared similar to a submucosal tumor and was histologically diagnosed as primary adenoid cystic carcinoma (ACC) of the esophagus. The patient has survived for 10 years postoperatively with no evidence of recurrence. Histologically, the tumor showed a cribriform, tubular or solid pattern. A small focus of squamous cell carcinoma (SCC) was found independently. Immunohistochemical results for keratin groups, S-100 protein and smooth muscle actin (αSMA) revealed similar profiles in the ACC tumor tissues and small ducts of the normal esphageal glands. By electron microscopy, tumor cells were found markedly similar to the small duct cells of the normal esophageal gland. These findings. indicate that ACC may originate from the esophageal glands, especially from cells of the small duct including intercalated duct.